It is well known that from time to time during the operation of an agricultural combine, blockages will occur in the feeder operable for conveying harvested crop material from a header to a threshing or separating system of the combine, and/or within the header, and/or at the interface between the header and the feeder where crop material enters the feeder. Typically, the feeder includes an upwardly and rearwardly inclined feeder housing containing a feeder conveyor mechanism which will typically include a forwardly located rotatable drum and rearwardly located drive sprockets encircled by at least two spaced apart, endless feeder chains connected together by slats. The drive sprockets are rotated to drive the feeder chains and slats in an upward and rearward direction along a floor of the feeder housing, such that the slats will engage and drag crop material conveyed by the header to an inlet opening of the feeder housing, through the inlet opening and onto the floor, so as to be thereafter conveyed upwardly and rearwardly along the floor by the slats, for induction into the inlet of the threshing or separating system. Also typically, the feeder conveyor mechanism and the powered mechanism or mechanisms of the header, i.e., harvesting mechanisms and conveyors thereof, are commonly driven by a belt or other drive system of the combine. Blockages of the flow of the crop material in the header, and/or jamming of operating mechanisms of the header, blockages in the vicinity of the inlet opening of the feeder, and along the floor of the feeder housing, can occur for a variety of reasons, such as a result of induction of a hard object, such as a downed fence post, a log; an animal carcass; a particularly large volume of crop material; a large wad of viny plants; and/or tall weeds. Such blockages can simply block induction of crop material into the header and/or the feeder, and/or result in stalling of the operation of the conveyor mechanism of the feeder and/or one or more operating mechanisms of the header, and therefore must be removed or dislodged.
A well known manner of removal or dislodgement of a blockage is to operate the feeder conveyor mechanism, and the jointly driven header mechanisms, in a reverse direction, that is, with regard to the feeder, wherein the feeder chains and slats are moved downwardly and forwardly along the feeder housing floor, such that the wad or other blockage is broken up and/or expelled from the feeder housing inlet back into the header. This reversal process is also often successful in unjamming mechanisms of the header and dislodging blockages thereof. After breakup or expulsion of the blockage, the feeder conveyor mechanism and header can typically then be operated in the normal direction.
Typically, a separate reversing drive is provided for the reverse operation of the feeder conveyor mechanism and the header. Reasons for this include that significantly increased drive force is often required for the dislodgment of a blockage, and that it is desirable to perform the reversing operation at a much slower speed than the normal feeder and header operation. Prior known reversing drive apparatus are disclosed in Duckinhaus U.S. Pat. No. 5,419,086, issued May. 30, 1995 to Claas Ohg, and Norton U.S. Pat. No. 5,462,486, issued Oct. 31, 1995. However, observed shortcomings of the apparatus disclosed in U.S. Pat. No. 5,419,086 include that it utilizes a pivoting support structure supporting the power unit which is pivotally supported at a location spaced a substantial distance from the power unit itself, so as possibly be less rigid than may be desirable, and that, when not in use, is suspended by a spring above a drive gear with which it is drivingly engaged during operation. A concern with this arrangement is that in the event of breakage and/or relaxation of the spring, or sudden downward jarring movements, violent contact between the gear of the power unit and the drive gear may occur, resulting in damage to one or both. Observed shortcomings of the apparatus disclosed in U.S. Pat. No. 5,462,486 include that it is relatively complex, for instance, as it requires an angular drive and a large number of components, that it relies on engagement between a drive sprocket thereof and a relatively short extent of drive chain for the forces necessary to be transmitted thereby for dislodgment of a blockage, which forces are often large in magnitude, and the feeder drive mechanism is depicted as comprising a long chain, which has been found to be an inefficient means of power transmission for feeder applications, compared to many alternative belt and/or shaft drives.
Thus, what is sought is a reverse drive engaging mechanism for a feeder and a header of a combine, which overcomes one or more of the shortcomings set forth above, is reliable, robust, and relatively inexpensive.